Fanatical Ashraf Islam promised Muslims they would be rewarded with a string of virgins if they launched mass murder in Britain.

The 30-year-old serial fraudster – who plotted to kill Prince Harry – is said to have launched a vile tirade of hate against ­Christians in an online manifesto.

Islam, known as Mark Townley before he became a Muslim, called the virgins of “tender age” “houris” in his crazed February rant.

He said: “Those who kill ­Christians would be given a good number of these houris to enjoy.

“The Prophet had also ordered his followers not to befriend Christians or talk with them.”

His outburst was written under the headline “Kill Christians”.

Ashraf Islam (Image: Twitter)

He quoted an Islamic holy book as the source for the virgins promise. Islam, originally from Northern Ireland, is thought to have been radicalised by hate preachers while locked up in ­Maghaberry prison, Lisburn.

He may face another 10 years behind bars after ­admitting to police he wanted Prince Harry dead.

Islam walked into a police station in Hounslow, West London, on May 25 – a day after Drummer Lee Rigby’s horrific murder in ­Woolwich.

The charge shows he intended to make the officer “fear the threat should be carried out”. He was arrested on the spot.

Islam was known by several aliases and has a string of fraud convictions for scamming people out of hundreds of ­thousands of pounds. He spent time on business in the Middle East in 2010 where he “ingratiated himself” with Muslim groups and handed himself in to police on fraud charges on his return.

During his spell in Maghaberry prison, he converted to Islam, changing his neat, business-like appearance to reflect his beliefs, adopting a shaven head, foot-long beard and long white robe. He changed his name and was known to use a mosque in Dublin.

Mark Townley aka Ashraf Islam

After his arrest over the Harry threat, police found evidence on Islam’s laptop that he visited terrorist and weapons websites and had searched for “kidnapping”, “guns” and “vans”.

A source said analysis of his computers had found “overwhelming” evidence that he was “of the terrorist type”. At a hastily arranged Saturday court hearing in Uxbridge. West London, Islam pleaded guilty to threats to kill. He was remanded in custody while a date is fixed for sentencing at Isleworth crown court.

The charge carries a 10-year maximum prison sentence.

Soldier Harry’s personal security is now being urgently ramped up in the wake of the threat. It was already under review in the wake of Lee’s killing.

The 28-year-old prince also faces calls to end his deployments to Afghanistan where he is considered a prime target for ­assassination by the Taliban. He gave a controversial interview during his time in the killing fields of Helmand in which he admitted killing insurgents.

Harry is reportedly being guarded around the clock by two armed SAS men.

A royal source said: “He is a target for many reasons and his protection officers know they have to be extremely vigilant. While there is relief this man has been caught, Harry’s security team are mindful this may be a sign of things to come.”

We can reveal Islam – of no fixed address but thought to have been living in West London before his arrest – once ran a ­business less than a mile from Kensington Palace, where Harry lives with the Duke and Duchess of Cambridge.

He has 32 ­convictions for fraud and deception and used a string of aliases, including the name of Star Wars actor Mark Hamill. In 2008 he got a six-month sentence suspended for conning two soldiers.

He claimed he could turn them into industry-certified close protection bodyguards for a fee of £250 each.

But when they turned up for training at the Brecon Beacons in Wales he was nowhere to be seen.

Later, at Liverpool crown court, he pleaded guilty to 14 separate offences of obtaining money by deception. Islam was also banned from England and Wales for two years.

But he carried on conning in Dublin where fleeced £750,000 from young women he claimed he could turn into ­professional models.

David Cameron will today make a Commons speech about Lee’s death after returning from his trip to Ibiza.